The effect of orthodontic tooth movement on the human pulpal blood flow

本研究的目的是使用激光多普勒流量计（LDF）来检测施加压力对牙髓血流（PBF）的影响。对参与者（年龄：24-31岁）的重要左上中切牙进行测量。短期（近似）20秒）的侵入力（约500 gf）施加到受检牙齿的切缘，并在距齿龈缘约2 mm处进行PBF测量，将不透明的黑色橡胶坝施加到受检牙齿。在7名受试者中的6名受试者中，观察到施力期间LDF通量信号降低，然而，降低不具有统计学显著性。使用4-Meta树脂将正畸托槽粘附到受检牙齿和上第一磨牙的唇侧表面。将不锈钢管粘固在距龈缘2 mm切缘处，确保测量探针的精确引导。将改良的实用弓（0.016 * 0.022英寸）接合到托架上，并激活以向所检查的牙齿施加连续的侵入力（约50 gf）。在施加侵入力之前、期间和之后重复测量PBF。此外，短期（20秒）手动控制的侵入力（50 gf，100 gf，200 gf）施加到检查的牙齿和PBF也被记录。持续的侵入力在施加力的过程中产生显著的PBF降低。短时间施加压力对PBF的影响不受连续施加压力的影响。结果表明，在正畸治疗过程中，压力的施加会导致牙髓血流的减少，而对牙髓血流的监测可以反映牙髓血流动力学的变化。

The purpose of the present study was to examine the effect of intrusive force application on the pulp blood flow (PBF) using laser Doppler flowmeter (LDF). Measurements were made in vital upper left central incisors of the participants (age : 24-31). Short-term (approx. 20 seconds) intrusive force (app. 500 gf) was applied to the incisal edge of the examined teeth, and PBF measurements were made at approximately 2 mm to the gingival margin with opaque black rubber dam application to the examined teeth. In 6 out of 7 subjects, reduction of the LDF flux signal during the force application was observed, however, the reduction was not statistically significant. Orthodontic brackets were adhered to the labial surface of the examined tooth and upper first molars using 4-META resin. A stainless steel tube was cemented at 2 mm incisal to the gingival margin securing an exact guidance for the measurement probe. A modified utility arch (0.016 * 0.022 inch) was engaged to the brackets and activated to exert continuous intrusive force (approximately 50 gf) to the examined tooth. PBF was repeatedly measured before, during and after the intrusive force application. In addition, short-term (20 seconds) manually-controlled intrusive force (50 gf, 100 gf, 200 gf) was applied to the examined tooth and PBF was also recorded. Continuous intrusive force produced significant reduction of PBF during the force application. The reduction of PBF produced by the short term intrusive force application was not effected by the continuous intrusive force application. Results obtained suggest that the intrusive force application produces reduction of PBF and that monitoring of PBF indicates the change of the pulpal haemodynamics during Orthodontic treatment.